1. Field of the Invention
The invention relates to a method and an apparatus for preventing machine damage in the event of a web break in web-fed rotary printing machines having a plurality of cylinders rolling on one another.
2. Description of the Related Art
In the event of a web break, there is the risk that the printing-material web, which loses tension because of the web break, remains stuck to a transfer cylinder because of the adhesive effect of the fresh printing ink and is therefore wound up on the said cylinder. In order to avoid damage caused by this to the rubber blankets and/or the cylinder bearings, in the event of a web break the cylinders are brought very quickly into the print-off position. In addition, use is made of knock-off or catching devices, as they are known, by means of which the free end of a torn printing-material web is cut or caught and wound up. Transferring the cylinders rapidly into the print-off position is undesirable, since this can cause further web breaks. In addition, the result may be impacts on the drive devices. The use of knock-off and catching devices requires a high outlay on their provision and requires a great deal of space.